Electrically-operated water heater



s. D. NESMITH ELECTRICALLY OPERATED WATER HEATER 2 Sheets-Sheet 1 Filed May 19. 1926 ,%NVENTOR I BY v ATTORNEYS.

Patented Aug 23, 1927.

UNITED STATES PATENT OFFICE.

SAMUEED. NESMITH, OF SAN DIEGO, CALIFORNIA, ASSIGN OR OF PART INTEREST TO GEORGE H. SCHMIDT, WALTER C. STITT, F. 1?. GRANT, H. M. SAMMIS, PAUL J.

HARTLEY, AND R. C. EASOM.

ELECTRICALLY-OPER ATED WATER HEATER.

My invention relates to an improvement in electrically operated water heaters, and it has for one of its objects the provision of an electrically operated water heater adapted 6 to be connected to a tank of water whereby the water will be caused to circulate through the apparatus and be heated thereby, my apparatus, however, being locatedat the exterior of the tank containing the water to be 10 heated, as distinguished from the immersion type of heater, wherein the heating element is located directly in the water. This arrangement is of material advantage as compared with the immersion type of heater in that it is not subjected to the c'orroding effect of the water, and the danger of charging the water with the power employed for operating the device is redufied to a minimum.

A still further object of my invention is to provide an electrically operated water heater of the character above indicated, wherein I employ a series of flattened water tubes of high heat conductivity, these tubes being arran ed in spaced relation to each other, electrical heating elementsindependently removable being interposed between adjacent tubes. These heating elements, I may say are of the proper shape and size to substantially fill the space between adjacent tubes so as to reduce to a minimum, in fact,

i practically eliminate, air spaces between the heating elements and the tubes, thereby promoting efficiency in the operation ofthedeyice, both as to method of application of the heat to the water and the amount of current consumed.

A- still further object of my invention is the provision of an apparatus such as above outllned, in which thewater tubes'are provided at each end with an annular flange, each tube preferably being composed of thin-walled flattened copper tubing, the annular flanges being welded thereto. This 46 provides an arrangement wherein, so far as heating is concerned, most efiicient operation is obtained. The tubes are also removably secured in position, thereby rendering the tubes accessible for removal and replace- 50 ment, each tube, it being understood, being removable independently of all the others.

Another and further object of my invention is the provision of an electrically operated water heater in which the thin-walled Application filed May 19,1926. Serial No. 110,078.

Water tubes of high heat conductivity are series connected, so that the water circulatmg .through the apparatus will be constrained to flow in a zig-zag or tortuous path, and for this reason be thoroughly heated as it emerges from the apparatus and is returned to the tank. This, it will be seen,-

insures a constant circulation of the water from the tank to the heater and back to the tank again, due to temperature changes in the water. If desired, athermostatic control may be employed so as to open the electric circuit of the apparatus after the temperature of the water has reached a predetermined point.

A still further object of my invention is the provlsion of an electrically 0 rated water heater in which'the water tu es are disposed horizontally and are independently attached, as by bolting, to a pair of spaced headers, each header being of unitaryor in-" tegral construction and so arranged or constrncted internally as to provide a series connection for the. tubes. These headers, as 1n the case of the water tubes and of the heating elements, may be readily removed for the purposes of inspection and repair or renewal, as the case may be, without necessitating the destruction of any part of the 1 ap aratus.

nother object of my invention is the pro-' In my improved device I have also provided means for thoroughly heat insulating the apparatus to retain, as far as possible,

all the heat generated therein, and I have also so constructed the heating elements employed as to eliminate all danger of charging of the water as it passes through the heater.

In the accompanying drawings;-

Fig. 1 shows an installation of my improved apparatus in more or less diagrammatic form,

Fig. 2 is a sectional side elevation or my improved heater;

Fig. 3 is a view taken substantially on the line 3-3 of Fig. 2;

- or unitary. Structure.

columns extendin of the water tubes is provided at each end with an annular flange desi ed or otherwise rmanent y attached to the tubes. The to are arranged horizontall and in spaced relation to each other, as plainly ated 2, welders 3 and 4. 'These two headers extend vertically of the apparatus across the ends of all the tubes, and each header is a one-piece The header 3 is provided with water passageways 5, while the header 4 is provided with similar water passageways 6 these water passa eways being so located with respect to the tu other as to connect the water tubes inseries. Each header is provided with bosses or columns 7 cast integral therewith, these from the-inner wall to the outer wallio their respective headers.

lies the joints This provides a construction whereby bolts 8 may be passed through the headers and into the flanges 2 on the water tubes without coming in contact with the water passing through the headers. I The bolts 8 constitute part of the means for attaching the water tubes to the headers. The additional attachin or securing means is provided by three bo ts designated 9 (see Fig. 3), these bolts passing througih the headers and into the flanges at one si e of the water passagewa s in the headers. The columns 7 provi e solid material between theports 10 in the headers, which material overlaps or over- 11 between adjacent flanges 2 on adjacent water tubes to provide a waterti ht structure.

nte osed between adjacent water tubes and substantiall filling this space, are electricall operate heating elements 12. Each one 0 these heating elements is in the form of a brick-like structure or body portion 13, of electric insulating material, spirally slotted at 14 and wound with conductor tape 15. -In order that each heating element may be thoroughly electrically insulated from the water tubes, the slots above the tape are filled with insulating material designated 16. The insulating material, em loyed in these heating elements is prefera ly alundum, inasmuch as I have found this to be a good electric insulator and yet a material which will retain its heat for a lon time, to maintain the water circulating through the water tubes in a heated condition some time after the electric power has been shut indicated in Fig. 2, and each tube 1s secured for independent removal to heads and to each 011. It is to be understood that each one of I these electric heating elements is so mounted asto be removable independently of the others and of the water tubes, so that if it is desired to remove any one of these heating elements for purposes of inspection, repair or replacement, this may readlly be done.

The conductors 15 of the heating elements may be connected to each other by the connector arrangement shown at 17 in Fig. 3. It will be understood that these conductors may be connected in series or in multiple, or in any other way electrically, that may be desired.

The headers 3 and 4, as already pointed out, are identical in construction, and the header 4 is provided with an inlet connection 18 while the header 3 is provided with an outlet connection 19. ThlS is the ideal arrangement in a heater of this kind, for the reason that it permits of the cold water being taken in at the bottom of the heater and the hot water to be taken off at the top, to which it will naturally rise.

On the exterior of the headers I provide a heat and electric insulating board or slab 20 extending from top to bottom of the heater and from end to end. At the top of the heater adjacent the uppermost tube 1, I provide an electric and insulating board 21-, while a similar board 22 is provided at the bottom of the heater against the lowermost water tube. On the exterior of these two last mentioned members I provide a metal plate, a plate 23 at the top and a plate 24 at the bottom. The plate 23 is flanged and connected to the flanges of the u per water tube and to theheaders by a bolt or bolts 25. The lower late 24 is held in place in a similar manner y .bolts 26. This provides, therefore, a unitary, rigid structure consisting of the headers, tubes, heaters and end plates or tie plates. On the exterior of the heater I provide a metal casing, preferably a sectional casing, designated 27, no which may readily be removed whenever accessis desired to the interior of the heater.

The connector shown at 17 in Fig. 3, by which the conductors of adjacent heating elements are connected to each other, comprises insulating members 28 and 29 arranged in spaced relation to each other and set into one of the boards or slabs of insulation 35. Intermediate these two members is another insulating member 30 recessed at 31 on its outer face. On the outside of this board and of the two members 28 and 29 is another insulator 32 recessed at 33. A connector comprised of two plates is set into the recess between the insulating members 32 and 30. By merely removing the board or slab 35, access may be had to this connector arran ement to disconnect the conductors of a jacent heating elements from each other, or for any other purpose desired.

i What I claim is:

1. An electrically operated water heater comprising in combination a plurality of series connected separate flattened water tubes, flanges on the ends of each tube, a header at each end of said tube bolted to said flanges to attach said tubes to said headers for independent removal and to connect said tubes in series, and independently removable electrical heating elements interposed between and adjacent said tubes and electrically insulated therefrom.

2. A n electrically operated Water heater comprising in combination a plurality of fiattenedwater tubes, flanges secured to the ends of'eachtube, unitary headers at each end of said tubes and to which said tubes through said flanges are attached to connect said tubes in series for independent removal, and independently removable electrical heating elements interposed between and adjacent said tubes and electrically insulated therefrom.

3. An electrically operated water heater comprising in combination a plurality of horizontally disposed, spaced, separate,

water tubes, a header at each end of said tubes arranged to connect the same in series, flanges attached to each end of each tube by which the tubes are connected to the headers for independent removal, and electric heating elements positioned between and adjacent the walls of said tubes and electrically insulated therefrom.

4. In an electrically operated water heater comprising in combination, a pair of vertically extendlngunitary spaced headers, a plurality of water tubes positioned between said hea ers, flanges on each end of each tube, each header being provided with water passageways to connect said tubes in series, .bolts for attaching said water tubes to said headers for independent removal said bolts passing through the said flanges on the tubes, and electrical heating elements interposed between adjacent tubes and filling the space between said tubes, said electrical heating elements bein independently removable.

This speci cation signed this 13th day i of May, 1926. v

' SAMUEL nNEsm'rH. 

